service backend

api/pkg/mutil/reorder/reorder.go

@@ -0,0 +1,42 @@
+package reorder
+
+import (
+	"github.com/tech/sendico/pkg/merrors"
+	"github.com/tech/sendico/pkg/model"
+)
+
+// IndexableRefs reorders a slice of IndexableRef items
+// Returns the reordered slice with updated indices, or an error if indices are invalid
+func IndexableRefs(items []model.IndexableRef, oldIndex, newIndex int) ([]model.IndexableRef, error) {
+	// Find the item to reorder
+	var targetIndex int = -1
+	for i, item := range items {
+		if item.Index == oldIndex {
+			targetIndex = i
+			break
+		}
+	}
+	if targetIndex == -1 {
+		return nil, merrors.InvalidArgument("Item not found at specified index")
+	}
+
+	// Validate new index bounds
+	if newIndex < 0 || newIndex >= len(items) {
+		return nil, merrors.InvalidArgument("Invalid new index for reorder")
+	}
+
+	// Remove the item from its current position
+	itemToMove := items[targetIndex]
+	items = append(items[:targetIndex], items[targetIndex+1:]...)
+
+	// Insert the item at the new position
+	items = append(items[:newIndex],
+		append([]model.IndexableRef{itemToMove}, items[newIndex:]...)...)
+
+	// Update indices
+	for i := range items {
+		items[i].Index = i
+	}
+
+	return items, nil
+}